This book is a contribution to the flourishing field of formal and philosophical work on truth and the semantic paradoxes. Our aim is to present several theories of truth, to investigate some of their model-theoretic, recursion-theoretic and proof-theoretic aspects, and to evaluate their philosophical significance. In Part I we first outline some motivations for studying formal theories of truth, fix some terminology, provide some background on Tarski’s and Kripke’s theories of truth, and then discuss the prospects (...) of classical type-free truth. In Chapter 4 we discuss some minimal adequacy conditions on a satisfactory theory of truth based on the function that the truth predicate is intended to fulfil on the deflationist account. We cast doubt on the adequacy of some non-classical theories of truth and argue in favor of classical theories of truth. Part II is devoted to grounded truth. In chapter 5 we introduce a game-theoretic semantics for Kripke’s theory of truth. Strategies in these games can be interpreted as reference-graphs of the sentences in question. Using that framework, we give a graph-theoretic analysis of the Kripke-paradoxical sentences. In chapter 6 we provide simultaneous axiomatizations of groundedness and truth, and analyze the proof-theoretic strength of the resulting theories. These range from conservative extensions of Peano arithmetic to theories that have the full strength of the impredicative system ID1. Part III investigates the relationship between truth and set-theoretic comprehen- sion. In chapter 7 we canonically associate extensions of the truth predicate with Henkin-models of second-order arithmetic. This relationship will be employed to determine the recursion-theoretic complexity of several theories of grounded truth and to show the consistency of the latter with principles of generalized induction. In chapter 8 it is shown that the sets definable over the standard model of the Tarskian hierarchy are exactly the hyperarithmetical sets. Finally, we try to apply a certain solution to the set-theoretic paradoxes to the case of truth, namely Quine’s idea of stratification. This will yield classical disquotational theories that interpret full second-order arithmetic without set parameters, Z2- . We also indicate a method to recover the parameters. An appendix provides some background on ordinal notations, recursion theory and graph theory. (shrink)

Quentin Smith has argued that the new tenseless theory of time is faced with insurmountable problems and should be abandoned in favour of the tensed theory of time. Smith;s main argument attacks the fundamental premise of the tenseless theory: that tenseless truth conditions for tokens of tensed sentences adequately capture the meaning of tensed sentences. His position is that tenseless truth conditions cannot explain the logical relations between tensed sentences, thus the tensed theory must be accepted. Against Smith, (...) this paper adopts an alternative approach to the explanation of the entailment relations between sentences which contain indexicals. The approach drops the reliance upon tokens and instead relies on the evaluation of sentence types with respect to a context rather than upon actual or possible utterances of tokens of the types. This (new) version of the tenseless theory of time can adequately explain the relevant entailment relations between tensed sentences. (shrink)

This paper is part of a broader project whose aim is to present a coherent unified approach to natural language dialogue semantics using tools from type theory. Here we explore aspects of our approach which relate to situation theory and situation semantics. We first point out a relationship between type theory and the Austinian notion of truth. We then consider how records in type theory might be used to represent situations and how dependent record types can be used (...) to model constraints on situations. We then sketch treatments of attitude phenomena for which Barwise and Perry proposed situation semantic analyses (perception complements, belief, the Pierre puzzle) as well as two other intensional phenomena (intensional verbs and intentional identity). Finally we give a characterisation of the type theory used and a small illustrative fragment of English. (shrink)

We present an overview of typed and untyped disquotational truth theories with the emphasis on their (non)conservativity over the base theory of syntax. Two types of conservativity are discussed: syntactic and semantic. We observe in particular that TB—one of the most basic disquotational theories—is not semantically conservative over its base; we show also that an untyped disquotational theory PTB is a syntactically conservative extension of Peano Arithmetic.

We study, from a classical point of view, how the truth of a statement about higher type functionals depends on the underlying model. The models considered are the classical set-theoretic finite type hierarchy and the constructively more meaningful models of continuous functionals, hereditarily effective operations, as well as the closed term model of Gödel's system T. The main results are characterisations of prenex classes for which truth in the full set-theoretic model transfers to truth in the other (...) models. As a corollary we obtain that the axiom of choice is not conservative over Gödel's system T with classical logic for closed ∃2-formulas. We hope that this study will contribute to a clearer delineation and perception of constructive mathematics from a classical perspective. (shrink)

In the paper we investigate typed axiomatizations of the truth predicate in which the axioms of truth come with a built-in, minimal and self-sufficient machinery to talk about syntactic aspects of an arbitrary base theory. Expanding previous works of the author and building on recent works of Albert Visser and Richard Heck, we give a precise characterization of these systems by investigating the strict relationships occurring between them, arithmetized model constructions in weak arithmetical systems and suitable set existence (...) axioms. The framework considered will give rise to some methodological remarks on the construction of truth theories and provide us with a privileged point of view to analyze the notion of truth arising from compositional principles in a typed setting. (shrink)

Using focus groups, this small-scale, qualitative study investigated the way that students tend to think about religious truth-claims as compared to other types of truth-claim. All the student participants conceived of religious truth-claims as ‘opinions’, to be contrasted with the certain, indisputable ‘facts’ of science. For many students, it was the lack of empirical verification, as well as the existence of disagreement, which meant religious beliefs were relegated to this position. If these findings are generalisable, then (...) there are implications for the ongoing theoretical dispute over the extent to which truth should be a focus in religious education. The tendency for students to see religious claims as subjective lends support for a critical pedagogy that places evaluation of truth centre-stage. The findings also suggest a need for religious education and science teachers to include more reflection on the nature of the scientific method in their schemes of work in order to dispel the myths of unanimity and certainty in science. (shrink)

A statement is said to be true when the historic state of affairs to which it is correlated by the demonstrative conventions (the ones to which it ‘refers’) is of a type with which the sentence used in making it is correlated by the descriptive conventions.

This introduction to mathematical logic starts with propositional calculus and first-order logic. Topics covered include syntax, semantics, soundness, completeness, independence, normal forms, vertical paths through negation normal formulas, compactness, Smullyan's Unifying Principle, natural deduction, cut-elimination, semantic tableaux, Skolemization, Herbrand's Theorem, unification, duality, interpolation, and definability. The last three chapters of the book provide an introduction to type theory (higher-order logic). It is shown how various mathematical concepts can be formalized in this very expressive formal language. This expressive notation facilitates proofs (...) of the classical incompleteness and undecidability theorems which are very elegant and easy to understand. The discussion of semantics makes clear the important distinction between standard and nonstandard models which is so important in understanding puzzling phenomena such as the incompleteness theorems and Skolem's Paradox about countable models of set theory. Some of the numerous exercises require giving formal proofs. A computer program called ETPS which is available from the web facilitates doing and checking such exercises. Audience: This volume will be of interest to mathematicians, computer scientists, and philosophers in universities, as well as to computer scientists in industry who wish to use higher-order logic for hardware and software specification and verification. (shrink)

This paper on post-truth politics argues that to the extent that one wants to understand political discourses generally (post-truth political discourses in particular), it is crucial to see them as circulating talk that performs rather than reports. This implies a shift in focus. Many react strongly to ‘post-truth’ assertions by appealing to evidence, objectivity, facts and truth. In this paper, it is suggested that, when analysing political discourses, there is no point asking, ‘Is it true?’ One (...) should rather ask, ‘What happens as a result?’ Understanding political discourses as performative demands that the resulting doing, transforming and changing may transcend established parameters and known patterns. That also means problematising the types of argument allowed, or discourse considered appropriate, in a given situation. What, then, is the force within the performative discourse driving transformation? What role does intention play? And who—if anybody—can be designated as the master of the discourse? One way of answering these questions is to broaden the perspective of what happens in verbal exchanges. The hearer-speaker relation is fundamental, one in which meaning is shaped and the performative force is formed. A political discourse in general, and a post-truth political discourse in particular, cannot do and perform—cannot function—in a vacuum. This evokes serious questions about accountability and responsibility and also about human action and freedom. (shrink)

This is part two of a two-part paper in which we develop an axiomatic theory of the relation of partial ground. The main novelty of the paper is the of use of a binary ground predicate rather than an operator to formalize ground. In this part of the paper, we extend the base theory of the first part of the paper with hierarchically typed truth-predicates and principles about the interaction of partial ground and truth. We show that our (...) theory is a proof-theoretically conservative extension of the ramified theory of positive truth up to. (shrink)

There is strong disagreement about whether indicative conditionals have truth values. In this paper, I present a new argument for the conclusion that indicative conditionals have truth values based on the claim that some true statements entail indicative conditionals. I then address four arguments that conclude that indicative conditionals lack truth values, showing them to be inadequate. Finally, I present further benefits to having a worldly view of conditionals, which supports the assignment of truth values to (...) indicative conditionals. I conclude that certain types of account of indicative conditionals, which have been ignored in the literature partly on the basis of assigning truth values to indicative conditionals, deserve consideration. (shrink)

In recent years, Nietzsche’s views on (natural) science attracted a considerable amount of scholarly attention. Overall, his attitude towards science tends to be one of suspicion, or ambivalence at least. My article addresses the “Nietzsche and science” theme from a slightly different perspective, raising a somewhat different type of question, more pragmatic if you like, namely: how to be a Nietzschean philosopher of science today? What would the methodological contours of a Nietzschean approach to present-day research areas (such as neuroscience, (...) astrophysics, synthetic biology or climate studies) amount to? In other words, my paper reflects a shift of focus from author studies to extrapolation. The design of my article is as follows. I will start with the question (already widely discussed in the expert literature) to what extent Friedrich Nietzsche (a classical philologist by training) managed to familiarise himself with the natural sciences of his epoch. Subsequently, I will outline some basic methodological and conceptual ingredients of Nietzsche’s philosophy of science, focussing on core issues such as “genealogy”, “interpretation”, “enhancement” and “truth”. Next, I will elucidate Nietzsche’s genealogical methodology with the help of three case studies (three representative samples if you will) taken from Nietzsche’s writings and dealing with physiology, astronomy and neuro-psychology respectively. Finally, I will present the methodological contours of a Nietzschean understanding of contemporary technoscience. (shrink)

The fact that the names of two philosophers who lived and worked in such different periods, under conditions of quite dissimilar cultures and civilizations, share the title of this article is in itself enough to require clarification. Nikolai Berdiaev, who belonged to a current of Russian philosophy that called itself mystical, hardly needs to be presented to the reader. Muhyiuddin ibn-'Arabi , the greatest mystic of the Arab Middle Ages, is known as the founder of a philosophical conception that was (...) later referred to as the "unity of being" and enjoyed broad popularity among Islamic thinkers, philosophers, and poets of the late Middle Ages. Moreover, motifs of this conception are not difficult to find in the works of contemporary literati enthralled by the ideas of Islamic mysticism, i.e., of Sufism. Hence these two outstanding figures can be compared on the common ground that they belonged to the current of philosophical thought of mankind that is called mysticism or mystical philosophy. Despite all the differences that doubtlessly exist among Russian, Arabic, and, let us say, European mysticism, there are also certain fundamental common features of this way of looking at the world that enable us to bring all these currents together under a single generic concept. (shrink)

In recent work on context­dependency, it has been argued that certain types of sentences give rise to a notion of relative truth. In particular, sentences containing predicates of personal taste and moral or aesthetic evaluation as well as epistemic modals are held to express a proposition (relative to a context of use) which is true or false not only relative to a world of evaluation, but other parameters as well, such as standards of taste or knowledge or an (...) agent. Thus, a sentence like chocolate tastes good would express a proposition p that is true or false not only at a world of evaluation, but relative to the additional parameter as well, such as a parameter of taste or an agent. I will argue that the sentences that apparently give rise to relative truth should be understood by relating them in a certain way to the first person. More precisely, such sentences express what I will call first­person­based genericity, a form of generalization that is based on or directed toward an essential first­person application of the predicate. The account differs from standard relative truth account in crucial respects: it is not the truth of the proposition expressed that is relative to the first person; the proposition expressed by a sentence with a predicate of taste rather has absolute truth conditions. Instead it is the propositional content itself that requires a first­personal cognitive access whenever it is entertained. This account, I will argue, avoids a range of problems that standard relative truth theories of the sentences in question face and explains a number of further peculiarities that such sentences display. (shrink)

Permissivism is the view that, sometimes, there is more than one doxastic attitude that is perfectly rationalised by the evidence. Impermissivism is the denial of Permissivism. Several philosophers, with the aim to defend either Impermissivism or Permissivism, have recently discussed the value of (im)permissive rationality. This paper focuses on one kind of value-conferring considerations, stemming from the so-called “truth-connection” enjoyed by rational doxastic attitudes. The paper vindicates the truth-connected value of permissive rationality by pursuing a novel strategy which (...) rests on two main planks: first, there is a distinction between a fine-grained and a coarse-grained type-individuation of belief-forming methods. Secondly, different kinds of decision-theoretic reasoning, i.e. expected-accuracy reasoning and accuracy-domination reasoning, must be paired with a fine-grained and a coarse-grained type-individuation of methods, respectively. I argue that while the first pair is wholly irrelevant to the question of the truth-connection, the second affords the means to a permissivist explanation of the truth-connected value of rationality. (shrink)

Truth pluralism offers the latest extension in the tradition of substantive theorizing about truth. While various forms of this thesis are available, most frameworks commit to domain reliance. According to domain reliance, various ways of being true, such as coherence and correspondence, are tied to discourse domains rather than individual sentences. From this follows that the truth of different types of sentences is accounted for by their domain membership. For example, sentences addressing ethical matters are true (...) if they cohere and those addressing extensional states of affairs if they correspond. By tying distinct truth-grounding properties to domains rather than individual sentences, truth pluralists avoid certain issues with definitional ambiguity and indeterminacy. I argue that contrary to the ideal situation, domains fail to provide the sought-after benefits of achieving definitional unambiguity and determinacy in the standard domain reliant pluralist frameworks. The reason is that, when combined with the inherently ambiguous nature of certain truth-relevant terms of sentences, fringe cases emerge, causing some of them to count as members of multiple domains. Consequently, some sentences end up being both true and false in the standard domain reliant pluralist frameworks, thus conflicting with both standard laws of non-contradiction and identity. Finally, I argue that truth pluralists should pay closer attention to the hitherto neglected question of inherent natural language ambiguity. (shrink)

This takes a closer look at the actual semantic behavior of apparent truth predicates in English and re-evaluates the way they could motivate particular philosophical views regarding the formal status of 'truth predicates' and their semantics. The paper distinguishes two types of 'truth predicates' and proposes semantic analyses that better reflect the linguistic facts. These analyses match particular independently motivated philosophical views.

It is a fundamental intuition about truth that the conditions under which a sentence is true are given by what the sentence asserts. My aim in this paper is to show that this intuition captures the concept of truth completely and correctly. This is conceptual deflationism, for it does not go beyond what is asserted by a sentence in order to define the truth status of that sentence. This paper, hence, is a defense of deflationism as a (...) conceptual account of truth. This defense is developed in four stages. In the first stage I present a distinction between two types of deflationism, conceptual and metaphysical. This is the central stage of the argument and its main conclusion is that conceptual deflationism when joined with the principle of bivalence is inconsistent with metaphysical deflationism, that is, conceptual deflationism together with bivalence entails a non-deflationary metaphysical account of truth. In the second and third stages of the argument I argue that the totality of the Tarskian biconditionals, when interpreted as definitional biconditionals, offers a description of the nature of truth. In the fourth, and final, stage of the argument I advance a positive case for conceptual deflationism. I explain how the revision theory of truth provides this sort of deflationism with its best evidence: a clear demonstration of its consistency and a compelling argument for its material adequacy. (shrink)

The majority of physicalists are type-B physicalists – believing that the phenomenal-physical truths are only knowable a posteriori. This paper aims to show why this view is misguided. The strategy is to design an agent who (1) has full general physical knowledge, (2) has phenomenal concepts, and yet (3) is wired such that she would be in a position to immediately work out the phenomenal-physical truths. I argue that this derivation yields a priori knowledge. The possibility of such a creature (...) entails that – contrary to type-B physicalism – there is not an ideal epistemic gap between the phenomenal and the physical truths. Out of this argument against type-B physicalism emerges a positive result: a new and compelling version of type-A physicalism, roughly a type-A phenomenal concept strategy. (shrink)

Two types of truth table tasks are used investigating mental representations of conditionals: a possibilities-based and a truth-based one. In possibilities tasks, participants indicate whether a situation is possible or impossible according to the conditional rule. In truth tasks participants evaluate whether a situation makes the rule true or false, or is irrelevant with respect to the truth of the rule. Comparing the two-option version of the possibilities task with the truth task in Experiment (...) 1, the possibilities task yields logical answer patterns whereas the truth task yields defective patterns. Adding the irrelevant option to the possibilities task in Experiment 2 leads to a considerable amount of defective patterns in the possibilities task, but still to more logical patterns in the possibilities task than in the truth task. Experiment 3 shows that directionality matters since rule-to-situation tasks yield more logical answer patterns than do situation-to-rule tasks. We conclude that both task types are not comparable as such since wording, number of options and directionality influence the results. (shrink)

Fitch's argument purports to show that if all truths are knowable then all truths are known. The argument exploits the fact that the knowledge predicate or operator is untyped and may thus apply to sentences containing itself. This article outlines a response to Fitch's argument based on the idea that knowledge is typed. The first part of the article outlines the philosophical motivation for the view, comparing it to the motivation behind typing truth. The second, formal part presents a (...) logic in which knowledge is typed and demonstrates that it allows nonlogical truths to be knowable yet unknown. (shrink)

The relativized propositional calculus is a system of Boolean formulas with query symbols. A formula in this system is called a one-query formula if the number of occurrences of query symbols is just one. If a one-query formula is a tautology with respect to a given oracle A then it is called a one-query tautology with respect to A. By extending works of Ambos-Spies (1986) and us (2002), we investigate the measure of the class of all oracles A such that (...) the set of all one-query tautologies with respect to A does not p-btt-reduce to A, where p-btt denotes polynomial-time bounded-truth-table. We show that certain Dowd-type generic oracles all belong to the class, and hence measure of the class is one. (shrink)

This paper deals with the truth-Conditions and the logic for vague languages. The use of supervaluations and of classical logic is defended; and other approaches are criticized. The truth-Conditions are extended to a language that contains a definitely-Operator and that is subject to higher order vagueness.

The subjects of this thesis are truth, grounding and dependence. The thesis consists of an introduction and five free-standing essays. The purpose of the introduction is not merely to summarize the papers, but to provide a general background to the discussions in the essays. The introduction is divided into four chapters, each of which splits into a number of sections and/or subsections. Chapter 1. concerns the notion of ontological dependence. I start by making a distinction between two different (...) class='Hi'>types of ontological dependence and discuss how well these notions deal with a number of philosophical issues. I then go on to consider the role that ontological dependence plays in hierarchies of natural kinds. In Chapter 2., I discuss a related notion, namely that of grounding. I sketch the theoretical framework by specifying the logical form of grounding statements and a set of structural principles that govern grounding. The chapter ends with a brief discussion on some philosophical applications of grounding. Chapter 3. deals with the notion of truthmaking and how it squares with the grounding framework developed in the previous chapter. I present the reader with the so-called Truthmaker Principle, and provide answers to a number of questions that it raises. The fourth and final chapter summarizes the five papers. The six essays are divided into three categories. Paper I deals with the notion of ontological dependence in hierarchies of natural kinds. Paper II concerns the notion of grounding and resemblance orderings among powers. Papers III, IV and V discuss various aspects of truthmaker theory. (shrink)

How can the presence of truth in art be philosophically justified? A fundamental question that can be answered in the wisdom of Mullā Ṣadrā, one of the most important philosophers of Islam. The importance of the question of the relationship between art and truth arises from the state of art in the present era. In fact, the degradation of reason in front of feeling from the nineteenth century until today has made the field of arts devoid of any (...) representation of the truth and caused the importance and originality of finding pleasure or evoking feelings in the arts. Therefore, with a philosophical approach and relying on the descriptive-analytical method, at first, it described the fundamental of truth and delusion, the unity of the world, and the known, practical reason and the function of imagination in shaping intellectual concepts based on Mullā Ṣadrā’s views, and then with relying on those principles, he has examined the formation of truth-based works of art. The most important conclusion of the article is that art is not the only product of the feelings and taste of its creator; Rather, the artist, in his understanding of the truth, prepares the ground for its manifestation in the work of art. With this characteristic, art finds a form of rational knowledge, and symbolic and mystical arts are among the most important examples of this type of artistic creation. (shrink)

In truth theory one aims at general formal laws governing the attribution of truth to statements. Gupta’s and Belnap’s revision-theoretic approach provides various well-motivated theories of truth, in particular T* and T#, which tame the Liar and related paradoxes without a Tarskian hierarchy of languages. In property theory, one similarly aims at general formal laws governing the predication of properties. To avoid Russell’s paradox in this area a recourse to type theory is still popular, as testified by (...) recent work in formal metaphysics by Williamson and Hale. There is a contingent Liar that has been taken to be a problem for type theory. But this is because this Liar has been presented without an explicit recourse to a truth predicate. Thus, type theory could avoid this paradox by incorporating such a predicate and accepting an appropriate theory of truth. There is however a contingent paradox of predication that more clearly undermines the viability of type theory. It is then suggested that a type-free property theory is a better option. One can pursue it, by generalizing the revision-theoretic approach to predication, as it has been done by Orilia with his system P*, based on T*. Although Gupta and Belnap do not explicitly declare a preference for T# over T*, they show that the latter has some advantages, such as the recovery of intuitively acceptable principles concerning truth and a better reconstruction of informal arguments involving this notion. A type-free system based on T# rather than T* extends these advantages to predication and thus fares better than P* in the intended applications of property theory. (shrink)

In VAGUENESS AND DEGREES OF TRUTH, Nicholas Smith develops a new theory of vagueness: fuzzy plurivaluationism. -/- A predicate is said to be VAGUE if there is no sharply defined boundary between the things to which it applies and the things to which it does not apply. For example, 'heavy' is vague in a way that 'weighs over 20 kilograms' is not. A great many predicates -- both in everyday talk, and in a wide array of theoretical vocabularies, from (...) law to psychology to engineering -- are vague. -/- Smith argues, based on a detailed account of the defining features of vagueness, that an accurate theory of vagueness must involve the idea that truth comes in degrees. The core idea of degrees of truth is that while some sentences are true and some are false, others possess intermediate truth values: they are truer than the false sentences, but not as true as the true ones. Degree-theoretic treatments of vagueness have been proposed in the past, but all have encountered significant objections. In light of these, Smith develops a new type of degree theory. Its innovations include a definition of logical consequence that allows the derivation of a classical consequence relation from the degree-theoretic semantics, a unified account of degrees of belief and their relationships with degrees of truth and subjective probabilities, and the incorporation of semantic indeterminacy -- the view that vague statements need not have unique meanings -- into the degree-theoretic framework. -/- As well as being essential reading for those working on vagueness, Smith's book provides an excellent entry-point for newcomers to the area -- both from elsewhere in philosophy, and from computer science, logic and engineering. It contains a thorough introduction to existing theories of vagueness and to the requisite logical background. (shrink)

Martin-Löf’s type theory stems simultaneously from Frege and Russell’s logic-ontological ideas and Husserl’s phenomenology. The article examines this intermediate status of type theory using as examples Martin-Löf ’s syntactical-semantic method and the role of evidence and canonical objects in his approach. Martin-Löf borrows the syntactical-semantic method from Frege and extends it drawing on Husserl’s theory of meaning. In type theory this method leads to the identity (isomorphism) of syntax and semantics (formal logic and formal ontology). Unlike traditional formal logic the (...) type theory is an interpreted system from the very beginning. Being intuitionistic, Martin-Löf ’s theory is based on the notion of proof, not truth. From the meaning theory point of view, it is a variant of proof-theoretic semantics (Gentzen, Prawitz, Dummett) which understands meaning as an object constructed according to certain rules. So understood, the proof is based on evidence, which allows us to associate it with the theory of intentionality by Husserl. The article compares Martin-Löf ’s type theory with Husserl’s intentionality theory, especially with the latter’s noematic component. We may consider type-theoretical rules for constructing objects and operating with them as a concretization and formalization of the phenomenological notion of noema. Both are explications of the more general concept of meaning. The article discusses the interrelation between notions of sense and meaning (Sinn, Bedeutung) in Frege, Husserl and Martin-Löf. This reveals the uncertainty of Martin-Löf ’s position in relation to meaning theories of Frege and Husserl. (shrink)

Definitional and axiomatic theories of truth -- Objects of truth -- Tarski -- Truth and set theory -- Technical preliminaries -- Comparing axiomatic theories of truth -- Disquotation -- Classical compositional truth -- Hierarchies -- Typed and type-free theories of truth -- Reasons against typing -- Axioms and rules -- Axioms for type-free truth -- Classical symmetric truth -- Kripke-Feferman -- Axiomatizing Kripke's theory in partial logic -- Grounded truth -- Alternative (...) evaluation schemata -- Disquotation -- Classical logic -- Deflationism -- Reflection -- Ontological reduction -- Applying theories of truth. (shrink)

In my paper , I noted that Fitch's argument, which purports to show that if all truths are knowable then all truths are known, can be blocked by typing knowledge. If there is not one knowledge predicate, ‘ K’, but infinitely many, ‘ K 1’, ‘ K 2’, … , then the type rules prevent application of the predicate ‘ K i’ to sentences containing ‘ K i’ such as ‘ p ∧¬ K i⌜ p⌝’. This provides a motivated response (...) to Fitch's argument so long as knowledge typing is itself motivated. It was the burden of my paper to explore the case that knowledge typing is as motivated as truth typing by drawing on the parallels between epistemic paradoxes generated by sentences of the kind ‘this sentence is unknown’ and semantic paradoxes generated by sentences such as ‘this sentence is untrue’. Given that typing truth is one of the acknowledged options for solving semantic paradoxes, if the parity argument succeeds it follows that epistemic typing is as well-motivated as truth typing and that the typing response to Fitch's argument is correspondingly strong.Halbach presents an apparent problem for this argument. Let ‘ N’ and ‘ P’, respectively, denote the necessity and possibility predicates, ‘ K 1’ the knowledge predicate of first type, and let ‘γ’ be a K-free sentence such that γ ↔¬ P⌜ K 1⌜γ⌝⌝; we know such a ‘γ’ exists by a standard diagonalization argument. If we assume that γ is knowable at the next knowledge type, that is, at type 1, and that the possibility typing does not interfere with the knowledge typing, a contradiction quickly ensues. Formally: γ ↔¬ P⌜ …. (shrink)

There are several types of truths. In this paper I focus on semantic truths, and within these on factual truths. These truths are attributed to statements. I review the theory of the truth proposed by Bunge and discuss some problems that it presents. I suggest that a theory of truth of factual statements should be complemented by a theory of relevance, and propose the basic tenets of it. Finally, I briefly discuss the nature of propositions and the (...) problem of scientific truth in the light of the presented semantic theory. (shrink)

The paper argues for the applicability of the notion of collective truth as opposed to distributive truth, that is, truth at times or possibilia taken in groups rather than individually. The underlying reasoning is that there are transtemporal and transworld relationships, e.g., those involving the relations of <being a descendant of> and <thinking about>. Relationships are (one type of) truth-makers. Hence, there are transtemporal and transworld truth-makers. Therefore, there is transtemporal and transworld truth, i.e., (...) collective truth. A semantics is developed (formalized in the appendix) which embodies the notion of collective truth, and which thereby, it is argued, has various advantages over standard intensional semantics. For example, it avoids a commitment to certain impossible entities. (shrink)

Two types of truth table task are used to examine people's mental representation of conditionals. In two within-participants experiments, participants either receive the same task-type twice (Experiment 1) or are presented successively with both a possibilities task and a truth task (Experiment 2). Experiment 3 examines how people interpret the three-option possibilities task and whether they have a clear understanding of it. The present study aims to examine, for both task-types, how participants' cognitive ability relates to (...) the classification of the truth table cases as irrelevant, and their consistency in doing so. Looking at the answer patterns, participants' cognitive ability influences their classification of the truth table cases: A positive correlation exists between cognitive ability and the number of false-antecedent cases classified as ?irrelevant?, both in the possibilities task and the truth task. This favours a suppositional representation of conditionals. (shrink)

According to act theories, propositions are structured cognitive act‐types. Act theories appear to make propositions inherently representational and truth‐evaluable, and to provide solutions to familiar problems with alternative theories, including Frege’s and Russell’s problems, and the third‐realm and unity problems. Act theories have critical problems of their own, though: acts as opposed to their objects are not truth evaluable, not structured in the right way, not expressed by sentences, and not the objects of propositional attitudes. I show (...) how identifying propositions with other cognitive event‐types, namely thoughts, has the perceived virtues of act theories without the defects. (shrink)